1. Field of the Invention
The present invention relates to an actuator for controlling motion.
2. Description of the Related Art
Robots, from industrial robots to humanoid robots, are widely used and can perform flexible articulated motions through actuators having a deceleration function.
In particular, within the robotics industry, which has rapidly developed in recent times, robotics mechanisms that have only been used in specific industrial fields are also being applied to broader industrial fields leading to a convergence of technologies. For example, home cleaning robots, programmable education robots, robot toys, entertainment robots, and so on, are being further developed and produced.
An actuator related to driving within robot technology is a very important part. Further, a major component that constitutes the actuator may be a decelerator. Various kinds of decelerators such as a gear-type decelerator, a rolling ball-type decelerator, a cycloid decelerator, and so on, may be used as the decelerator.
Here, the gear-type decelerator, which is a widely used general decelerator, is a decelerator using an involute tooth form; the rolling ball-type decelerator is a decelerator in which a ball rolls in a guide groove having an epicycloid curve and a hypocycloid curve facing each other to perform deceleration rotation; a harmonic drive decelerator is a decelerator in which, when an oval wave generator assembly is rotated, an elliptically moving portion is transmitted to a flexspline by an elliptically revolving bearing and the flexspline is slowly rotated while skipping the outermost ring gear to induce deceleration; and the cycloid decelerator is a decelerator in which a trochoid gear serving as a planetary gear is eccentrically rotated while fixing a pin, and only the trochoid gear is rotated by a pinhole and the pin disposed in a trochoid at the same angular interval to obtain deceleration rotation.
Among these, in particular, since the cycloid decelerator can implement various deceleration ratios and is advantageous for high precision and high deceleration, the cycloid decelerator is widely used in fields that require precise control. Related technologies of the decelerator are disclosed in Korean Utility Model Registration No. 0325018 and Korean Patent Laid-open Publication Nos. 2010-0038146 and 2011-0068500.
However, considering the various decelerators including the above-mentioned related technologies, since the deceleration gear is installed in one housing, the size of the decelerator is increased and a user cannot easily set the deceleration ratio. In addition, the user cannot flexibly select his/her requirements (e.g., a center distance, a gear-type, a gear ratio, and the like).